Idaho 2025 Income Tax Filing Update and Conformity Changes

tax.idaho.gov

Published March 13th, 2026

Detected March 17th, 2026

Summary

The Idaho State Tax Commission issued an update regarding 2025 income tax filings, resolving an e-filing rejection issue for business returns and reminding taxpayers of new conformity deductions. The notice details changes for both individual and business taxpayers, including standard deduction amounts and research and experimentation expenditures.

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What changed

The Idaho State Tax Commission has issued a notice addressing updates for the 2025 Idaho income tax filing season. This notice clarifies that a technical issue causing rejections for some e-filed business returns has been resolved, allowing tax preparers to resubmit these returns. It also highlights new conformity deductions available to taxpayers, including larger standard deductions, enhanced senior deductions, and deductions for tips, car loan interest, and overtime compensation for individuals. Businesses will see changes related to research and experimentation expenditures and bonus depreciation.

Taxpayers who previously filed returns before these conformity deductions were available are advised to file an amended return, with the exception of those who already filed using the old standard deduction amount, who will automatically receive the updated amount. Businesses are encouraged to review updated instructions or consult their tax accountants. The notice also provides refund timeframes and reiterates the tax filing deadline of April 15.

What to do next

Resubmit rejected 2025 business income tax returns.
File amended returns for taxpayers who filed before conformity deductions were available, if applicable.
Review updated business income tax form instructions for changes to research and experimentation expenditures and bonus depreciation.

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Latest update on filing 2025 Idaho income taxes

Friday March 13, 2026 BOISE, Idaho — March 13, 2026 — The Idaho State Tax Commission reports that a recent issue caused some e-filed 2025 business income tax returns to be rejected by the state. The Tax Commission has resolved the issue, and tax preparers can resubmit these business returns. The issue was unrelated to the conformity updates.

The Tax Commission is also reminding taxpayers they can now file their 2025 Idaho income tax returns to claim all the new conformity deductions.

The deductions for individuals include the larger standard deduction amounts, the enhanced senior deduction, and the deductions for tips from wages, car loan interest, and overtime compensation.

If filing a Form 40, taxpayers will follow the instructions for line 18 to claim their deductions. If taxpayers use Form 43, they’ll follow the instructions for line 40. Form 43 filers will also fill out and keep a new worksheet, Idaho Worksheet 1-A, to help them determine their deductions.

Taxpayers who filed a return before the conformity deductions were available will need to file an amended return to claim them, except for the larger standard deduction. Anyone who’s already filed using the old standard deduction amount will automatically get the larger standard deduction.

For businesses, conformity brings changes to the deduction for research and experimentation expenditures and bonus depreciation. Businesses should review the instructions for business income tax forms for more information or consult their tax accountant.

Refund timeframes:

Taxpayers who file before March 10 can expect their refund by the end of May.
Those filing on or after March 10 can expect their refund within the Tax Commission’s normal timeframes: 7-8 weeks for e-filed returns and 10-11 weeks for paper returns. Visit tax.idaho.gov to get tax forms, make payments, and find tax help. You can also get help by calling (208) 334-7660 in the Boise area or toll free at (800) 972-7660.

The deadline to file 2025 income taxes is Wednesday, April 15.

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